[Android] Add enhanced bookmarks grid/list view experiment

BUG=490717

Review URL: https://codereview.chromium.org/1143153010

Cr-Commit-Position: refs/heads/master@{#332957}

4 files changed, 39 insertions, 2 deletions

diff --git a/components/enhanced_bookmarks/BUILD.gn b/components/enhanced_bookmarks/BUILD.gn
index 7395daa..ad55816 100644
--- a/components/enhanced_bookmarks/BUILD.gn
+++ b/components/enhanced_bookmarks/BUILD.gn
@@ -59,13 +59,14 @@ source_set("enhanced_bookmarks") {
 }
 
 if (is_android) {
-  # GYP: //components/enhanced_bookmarks.gypi:enhanced_bookmarks_launch_location_srcjar
-  java_cpp_enum("enhanced_bookmarks_launch_location_srcjar") {
+  # GYP: //components/enhanced_bookmarks.gypi:enhanced_bookmarks_java_enums_srcjar
+  java_cpp_enum("enhanced_bookmarks_java_enums_srcjar") {
     sources = [
       "enhanced_bookmark_utils.h",
     ]
     outputs = [
       "org/chromium/chrome/browser/enhanced_bookmarks/LaunchLocation.java",
+      "org/chromium/chrome/browser/enhanced_bookmarks/ViewMode.java",
     ]
   }
 }
diff --git a/components/enhanced_bookmarks/DEPS b/components/enhanced_bookmarks/DEPS
index 114b12c..1a3fa5a 100644
--- a/components/enhanced_bookmarks/DEPS
+++ b/components/enhanced_bookmarks/DEPS
@@ -4,6 +4,7 @@ include_rules = [
   "+components/pref_registry",
   "+components/signin",
   "+components/sync_driver",
+  "+components/variations",
   "+google_apis/gaia",
   "+jni",
   "+net",
diff --git a/components/enhanced_bookmarks/enhanced_bookmark_utils.cc b/components/enhanced_bookmarks/enhanced_bookmark_utils.cc
index 1ca96ca..7108d98 100644
--- a/components/enhanced_bookmarks/enhanced_bookmark_utils.cc
+++ b/components/enhanced_bookmarks/enhanced_bookmark_utils.cc
@@ -5,12 +5,15 @@
 #include "components/enhanced_bookmarks/enhanced_bookmark_utils.h"
 
 #include "components/bookmarks/browser/bookmark_model.h"
+#include "components/variations/variations_associated_data.h"
 
 using bookmarks::BookmarkModel;
 using bookmarks::BookmarkNode;
 
 namespace enhanced_bookmarks {
 
+const char kFieldTrialName[] = "EnhancedBookmarks";
+
 std::vector<const BookmarkNode*> PrimaryPermanentNodes(BookmarkModel* model) {
   DCHECK(model->loaded());
   std::vector<const BookmarkNode*> nodes;
@@ -63,4 +66,19 @@ const BookmarkNode* RootLevelFolderForNode(const BookmarkNode* node,
   return top;
 }
 
+ViewMode GetDefaultViewMode() {
+  std::string default_view_mode = variations::GetVariationParamValue(
+      enhanced_bookmarks::kFieldTrialName, "DefaultViewMode");
+
+  if (default_view_mode == "List") {
+    return ViewMode::LIST;
+  } else if (default_view_mode == "Grid") {
+    return ViewMode::GRID;
+  }
+
+  // If finch data is not available or has an invalid value, we fall back to
+  // ViewMode::GRID.
+  return ViewMode::GRID;
+}
+
 }  // namespace enhanced_bookmarks
diff --git a/components/enhanced_bookmarks/enhanced_bookmark_utils.h b/components/enhanced_bookmarks/enhanced_bookmark_utils.h
index c66fa9a..81476eb 100644
--- a/components/enhanced_bookmarks/enhanced_bookmark_utils.h
+++ b/components/enhanced_bookmarks/enhanced_bookmark_utils.h
@@ -16,6 +16,8 @@ class BookmarkNode;
 
 namespace enhanced_bookmarks {
 
+extern const char kFieldTrialName[];
+
 // Possible locations where a bookmark can be opened from.
 // Please sync with the corresponding histograms.xml.
 //
@@ -31,6 +33,16 @@ enum LaunchLocation {
   COUNT = 6,
 };
 
+// View modes of enhanced bookmarks' main items UI.
+//
+// A Java counterpart will be generated for this enum.
+// GENERATED_JAVA_ENUM_PACKAGE: org.chromium.chrome.browser.enhanced_bookmarks
+enum ViewMode {
+  DEFAULT = 0,
+  LIST = 1,
+  GRID = 2,
+};
+
 // Returns the permanent nodes whose url children are considered uncategorized
 // and whose folder children should be shown in the bookmark menu.
 // |model| must be loaded.
@@ -54,6 +66,11 @@ const bookmarks::BookmarkNode* RootLevelFolderForNode(
     const bookmarks::BookmarkNode* node,
     bookmarks::BookmarkModel* model);
 
+// Returns the default view mode for main items UI.
+// The default is controlled by a finch experiment. If finch is not available or
+// has an invalid value, it returns a hard coded default view mode.
+ViewMode GetDefaultViewMode();
+
 }  // namespace enhanced_bookmarks
 
 #endif  // COMPONENTS_ENHANCED_BOOKMARKS_ENHANCED_BOOKMARK_UTILS_H_